The number of atoms per unit cell in primitive (sc), body-centered (bcc), face-centered (fcc) and end- centered (ecc) unit cell decreases as

No. of atoms Arrangement Per unit cell 4 Fcc 2 Bcc 2 Ecc 1 simple cubic 72. A fcc unit of aluminium contains the equivalent of how many atoms? (a) 1 (b) 2 (c) 3 (d) 4 Each atom contributes 1 8 to the cube. Number of atoms in the corner = 1 8 1 8 x There are 6 face centers. Each atom contributes 1 2 to the cube. Number of atoms = 1 6 3 2 x Z = 4 SOLID STATE 11 Hence the correct answer is option (d)